1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
4 *
5 * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
6 */
7#include <linux/bitops.h>
8#include <linux/iio/iio.h>
9#include <linux/iio/sysfs.h>
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/regulator/consumer.h>
13#include <linux/regmap.h>
14#include <linux/spi/spi.h>
15
16#define LTC1660_REG_WAKE	0x0
17#define LTC1660_REG_DAC_A	0x1
18#define LTC1660_REG_DAC_B	0x2
19#define LTC1660_REG_DAC_C	0x3
20#define LTC1660_REG_DAC_D	0x4
21#define LTC1660_REG_DAC_E	0x5
22#define LTC1660_REG_DAC_F	0x6
23#define LTC1660_REG_DAC_G	0x7
24#define LTC1660_REG_DAC_H	0x8
25#define LTC1660_REG_SLEEP	0xe
26
27#define LTC1660_NUM_CHANNELS	8
28
29static const struct regmap_config ltc1660_regmap_config = {
30	.reg_bits = 4,
31	.val_bits = 12,
32};
33
34enum ltc1660_supported_device_ids {
35	ID_LTC1660,
36	ID_LTC1665,
37};
38
39struct ltc1660_priv {
40	struct spi_device *spi;
41	struct regmap *regmap;
42	struct regulator *vref_reg;
43	unsigned int value[LTC1660_NUM_CHANNELS];
44	unsigned int vref_mv;
45};
46
47static int ltc1660_read_raw(struct iio_dev *indio_dev,
48		struct iio_chan_spec const *chan,
49		int *val,
50		int *val2,
51		long mask)
52{
53	struct ltc1660_priv *priv = iio_priv(indio_dev);
54
55	switch (mask) {
56	case IIO_CHAN_INFO_RAW:
57		*val = priv->value[chan->channel];
58		return IIO_VAL_INT;
59	case IIO_CHAN_INFO_SCALE:
60		*val = regulator_get_voltage(priv->vref_reg);
61		if (*val < 0) {
62			dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
63					*val);
64			return *val;
65		}
66
67		/* Convert to mV */
68		*val /= 1000;
69		*val2 = chan->scan_type.realbits;
70		return IIO_VAL_FRACTIONAL_LOG2;
71	default:
72		return -EINVAL;
73	}
74}
75
76static int ltc1660_write_raw(struct iio_dev *indio_dev,
77		struct iio_chan_spec const *chan,
78		int val,
79		int val2,
80		long mask)
81{
82	struct ltc1660_priv *priv = iio_priv(indio_dev);
83	int ret;
84
85	switch (mask) {
86	case IIO_CHAN_INFO_RAW:
87		if (val2 != 0)
88			return -EINVAL;
89
90		if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
91			return -EINVAL;
92
93		ret = regmap_write(priv->regmap, chan->channel,
94					(val << chan->scan_type.shift));
95		if (!ret)
96			priv->value[chan->channel] = val;
97
98		return ret;
99	default:
100		return -EINVAL;
101	}
102}
103
104#define LTC1660_CHAN(chan, bits) {			\
105	.type = IIO_VOLTAGE,				\
106	.indexed = 1,					\
107	.output = 1,					\
108	.channel = chan,				\
109	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
110	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
111	.scan_type = {					\
112		.sign = 'u',				\
113		.realbits = (bits),			\
114		.storagebits = 16,			\
115		.shift = 12 - (bits),			\
116	},						\
117}
118
119#define  LTC1660_OCTAL_CHANNELS(bits) {			\
120		LTC1660_CHAN(LTC1660_REG_DAC_A, bits),	\
121		LTC1660_CHAN(LTC1660_REG_DAC_B, bits),	\
122		LTC1660_CHAN(LTC1660_REG_DAC_C, bits),	\
123		LTC1660_CHAN(LTC1660_REG_DAC_D, bits),	\
124		LTC1660_CHAN(LTC1660_REG_DAC_E, bits),	\
125		LTC1660_CHAN(LTC1660_REG_DAC_F, bits),	\
126		LTC1660_CHAN(LTC1660_REG_DAC_G, bits),	\
127		LTC1660_CHAN(LTC1660_REG_DAC_H, bits),	\
128}
129
130static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
131	[ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
132	[ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
133};
134
135static const struct iio_info ltc1660_info = {
136	.read_raw = &ltc1660_read_raw,
137	.write_raw = &ltc1660_write_raw,
138};
139
140static int __maybe_unused ltc1660_suspend(struct device *dev)
141{
142	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
143						to_spi_device(dev)));
144	return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
145}
146
147static int __maybe_unused ltc1660_resume(struct device *dev)
148{
149	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
150						to_spi_device(dev)));
151	return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
152}
153static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
154
155static int ltc1660_probe(struct spi_device *spi)
156{
157	struct iio_dev *indio_dev;
158	struct ltc1660_priv *priv;
159	const struct spi_device_id *id = spi_get_device_id(spi);
160	int ret;
161
162	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
163	if (indio_dev == NULL)
164		return -ENOMEM;
165
166	priv = iio_priv(indio_dev);
167	priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
168	if (IS_ERR(priv->regmap)) {
169		dev_err(&spi->dev, "failed to register spi regmap %ld\n",
170			PTR_ERR(priv->regmap));
171		return PTR_ERR(priv->regmap);
172	}
173
174	priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
175	if (IS_ERR(priv->vref_reg)) {
176		dev_err(&spi->dev, "vref regulator not specified\n");
177		return PTR_ERR(priv->vref_reg);
178	}
179
180	ret = regulator_enable(priv->vref_reg);
181	if (ret) {
182		dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
183				ret);
184		return ret;
185	}
186
187	priv->spi = spi;
188	spi_set_drvdata(spi, indio_dev);
189	indio_dev->info = &ltc1660_info;
190	indio_dev->modes = INDIO_DIRECT_MODE;
191	indio_dev->channels = ltc1660_channels[id->driver_data];
192	indio_dev->num_channels = LTC1660_NUM_CHANNELS;
193	indio_dev->name = id->name;
194
195	ret = iio_device_register(indio_dev);
196	if (ret) {
197		dev_err(&spi->dev, "failed to register iio device: %d\n",
198				ret);
199		goto error_disable_reg;
200	}
201
202	return 0;
203
204error_disable_reg:
205	regulator_disable(priv->vref_reg);
206
207	return ret;
208}
209
210static int ltc1660_remove(struct spi_device *spi)
211{
212	struct iio_dev *indio_dev = spi_get_drvdata(spi);
213	struct ltc1660_priv *priv = iio_priv(indio_dev);
214
215	iio_device_unregister(indio_dev);
216	regulator_disable(priv->vref_reg);
217
218	return 0;
219}
220
221static const struct of_device_id ltc1660_dt_ids[] = {
222	{ .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
223	{ .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
224	{ /* sentinel */ }
225};
226MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
227
228static const struct spi_device_id ltc1660_id[] = {
229	{"ltc1660", ID_LTC1660},
230	{"ltc1665", ID_LTC1665},
231	{ /* sentinel */ }
232};
233MODULE_DEVICE_TABLE(spi, ltc1660_id);
234
235static struct spi_driver ltc1660_driver = {
236	.driver = {
237		.name = "ltc1660",
238		.of_match_table = ltc1660_dt_ids,
239		.pm = &ltc1660_pm_ops,
240	},
241	.probe	= ltc1660_probe,
242	.remove = ltc1660_remove,
243	.id_table = ltc1660_id,
244};
245module_spi_driver(ltc1660_driver);
246
247MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
248MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
249MODULE_LICENSE("GPL v2");
250